Study On The Novel Structures Of GaN Gunn Diode

Terahertz(THz) technology is a new research area which has made rapid development recently. It is also an important manifestation of national competitiveness and comprehensive strength, and thus has a wide variety of applications. Among all the Terahertz sources, semiconductor solid state sources is of great importance. Compared to other conventional semiconductor material, Ga N has larger electron effective mass, higher two dimension electron gas concentration and faster electron scattering between sub-band. So it attracts widespread attention in the region of millimeter wave, high power electronic devices. For Gunn diode, the proposed structures include: n+/n-/n+ structure, notch doping structure, Al Ga N electron injector structure and so on. In order to reduce the length of “death region” and reduce the lattice mismatch in Al Ga N/Ga N heterojunction, We study and propose some novel structures of Gunn diode, including Al Ga N/Ga N superlattice electron injector structure, dual linearly graded Al content Al Ga N electron injector structure and Al Ga N layer in the ohmic contact region. Then we verify the rationality of the novel Gunn diode structures by simulation, extract electrical parameters, discuss the advantages of these device structures.For the Al Ga N/Ga N superlattice electron injector structure, first we select the appropriate DC operating point by simulation, get stable self-oscillation waveform and verify its rationality. Then we study the influence of the number of superlattice period and bias voltage on the device, get the general law and explain it using electric field distribution in the Gunn diode.To solve the problem in the injector layer of single linearly graded Al content Al Ga N elcctron injector structure,we propose a dual linearly graded Al content Al Ga N electron injector structure on the base of the Al Ga N/Ga N heterojunction theory. For this structure we first select the appropriate DC operating point by simulation and get stable self-oscillation. Then, we extract electrical parameters using fast Fourier transform,compare the difference with the single linearly graded Al content one.Finally, Aiming to resolve the problem of notch doping Ga N Gunn diode, we propose a new optimization program which introduce an Al Ga N electron injector layer in the ohmic contact region.For the new program we illustrate the design ideas, do electrical simulation for the new structure, verify the rationality, and present the simple manufacturing process. We also explain that the structure is suitable for other Ga N Terahertz devices.